CMC Medical CMC-Medical VELLORE Solved Paper-2013

  • question_answer
    If the potential of a capacitor having capacity \[6\mu F\]is increased from 10 V to 20 V then increase in its energy is

    A)  \[12\times {{10}^{-6}}J\]                             

    B)  \[9\times {{10}^{-4}}J\]

    C)  \[4.5\times {{10}^{-6}}J\]                           

    D)  \[2.25\times {{10}^{-6}}J\]

    Correct Answer: B

    Solution :

                    Capacitance of capacitor \[=6\mu F=6\times {{10}^{-6}}F\] Initial potential \[{{v}_{1}}=10\,\,V\] Final potential \[{{v}_{2}}=20\,\,V\] The increases in the energy is given by \[\Delta U=\frac{1}{2}C(v_{2}^{2}-v_{1}^{2})\] \[\Delta U=\frac{1}{2}\times 6\times {{10}^{-6}}[{{(20)}^{2}}-{{(10)}^{2}}]\] \[\Delta U=3\times {{10}^{-6}}\times 300\] \[\Delta U=9\times {{10}^{-4}}J\]


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